(Updated January 1, 2010)
D23 is Disney's latest, and best to date, attempt at a Fan Club. With a Magazine, EXPO, Fan Events, and Web Site, D23 is really coming into its own as a great fan experience. The price is $74.99 per person for a full membership (with magazine), and $34.99 without the magazine.
If you haven't signed up and are looking to take the plunge, here is the link to Sign Up For D23
We'll sticky this thread as a resource for those looking for information on where to sign up.
PS - Please keep your confirmation email after you sign up - it contains your member number.